How to let application create tap network device inside the container (softether client)?

As in the title. I need a way to allow the softether to install /dev/vpn_se tap device.

$ lxc config device add CONTAINER_NAME tap unix-char path=/dev/net/vpn_se
Error: Failed to start device 'tap': The required device path doesn't exist and the major and minor settings are not specified

I use usermode lxd container.

Have a look at this issue here:

It shows a command to get the tun device into a container, which should be similar to how to get the tap device into a container.